Some corrections to Annex 4B were introduced when that Annex was merged into the new Annex 4 in Revision 6 of UN R49. These corrections were not carried over into Annex 4B as it stands in Revision 5; however, some of these are necessary for dual-fuel engines and vehicles. The chair of the GFV Heavy-duty Dual Fuel Task Force has prepared this document to correct the oversight.